Burweed is a common nuisance in many lawns and gardens, recognized for its distinctive, prickly seed pods. This article details the key features that help distinguish burweed from other plants, focusing on its overall appearance, leaf characteristics, and defining burs.
Overall Appearance and Growth Habit
Burweed, often referred to as lawn burweed or sticker weed, grows as a low-lying, mat-forming annual plant. It creates dense, spreading patches that can quickly cover areas of turf. The plant reaches a height of only 1 to 3 inches, hugging the ground closely. From a distance, its overall color can appear light to medium green, blending somewhat with healthy grass before its burs become prominent. Its prostrate growth habit allows it to withstand mowing, further aiding its spread in maintained areas.
Distinctive Leaves
The leaves of burweed provide a clear identification marker due to their finely divided, fern-like structure. Each leaf is small, measuring less than an inch in length, and is deeply lobed into narrow segments. These segments give the foliage a delicate, almost feathery appearance. The leaves are arranged alternately along the stem and are a bright to light green color, often contrasting slightly with darker turf grasses. This unique leaf shape helps differentiate burweed even before its burs are fully developed.
The Defining Burs
The most characteristic feature of burweed, and the source of its common name, is its small, spiny bur. These burs develop from inconspicuous, greenish-yellow flowers that form in the leaf axils in late winter to early spring. Initially green, the burs mature and dry to a light brown or straw color, becoming rigid and sharp. Each bur is roughly spherical or egg-shaped, measuring about 0.1 to 0.2 inches in diameter, and is covered with numerous stiff, pointed spines. These spines are designed for dispersal, readily clinging to skin, clothing, shoes, and pet fur, causing considerable discomfort.
Common Habitats and Seasonal Appearance
Burweed thrives in a variety of environments, particularly in thin, open turf areas where competition from other plants is reduced. It is frequently found in lawns, sports fields, and other disturbed sites with compacted or sandy soils. This weed emerges in cooler seasons, often in late fall or early winter, and continues to grow through the spring. The prickly burs become most noticeable and problematic from late spring through early summer as the plant completes its life cycle and dries out. Identifying burweed early in its growth cycle, before the burs harden, aids management.